Electric double layer capacitors being one example of capacitors have been developed as power storage devices for power-assisting and backing up electronic devices. In this situation, as a result of repeatedly conducting studies on activated carbon for capacitors in order to achieve life prolongation by maintaining charge-discharge characteristics, it has been found that this purpose can be achieved by using activated carbon containing a predetermined amount of metal components that have been heretofore removed as impurities.
It is known that activated carbon, which is produced from coal containing 1800 ppm to 5000 ppm of iron and which has an average particle size of 1 μm to 50 μm, a BET specific surface area of 2000 m2/g or more and a pore volume of 1 mL/g or more, and contains 1800 ppm to 5000 ppm of iron, has been heretofore used as activated carbon for capacitors.
As prior art document information related to the present application, for example PTL 1 is known.